fix prov bug, update release note

Author: qqmyers

doc/release-notes/ 11142-more detailed file differences.md

@@ -1 +1 @@
-The file page version table now shows whether a file has been replaced. 
+The file page version table now shows more detail, e.g. when there are metadata changes or whether a file has been replaced. 

src/main/java/edu/harvard/iq/dataverse/DatasetVersionDifference.java

@@ -373,9 +373,9 @@ public static Map<String,List<String>> compareFileMetadatas(FileMetadata fmdo, F
                     List.of(fmdo.getLabel(), fmdn.getLabel()));
         }
 
-        if (!StringUtils.equals(fmdo.getProvFreeForm(), fmdn.getProvFreeForm())) {
+        if (!StringUtils.equals(StringUtil.nullToEmpty(fmdo.getProvFreeForm()), StringUtil.nullToEmpty(fmdn.getProvFreeForm()))) {
             fileMetadataChanged.put("ProvFreeForm",
-                    List.of(fmdo.getProvFreeForm(), fmdn.getProvFreeForm()));
+                    List.of(StringUtil.nullToEmpty(fmdo.getProvFreeForm()), StringUtil.nullToEmpty(fmdn.getProvFreeForm())));
         }
 
         if (fmdo.isRestricted() != fmdn.isRestricted()) {